/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.factory.support;

import java.lang.reflect.Method;

import org.springframework.beans.BeanMetadataElement;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;

/**
 * Object representing the override of a method on a managed object by the IoC
 * container.
 *
 * <p>Note that the override mechanism is <em>not</em> intended as a generic
 * means of inserting crosscutting code: use AOP for that.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Sam Brannen
 * @since 1.1
 */
public abstract class MethodOverride implements BeanMetadataElement {

    private final String methodName;

    private boolean overloaded = true;

    @Nullable
    private Object source;


    /**
     * Construct a new override for the given method.
     *
     * @param methodName the name of the method to override
     */
    protected MethodOverride(String methodName) {
        Assert.notNull(methodName, "Method name must not be null");
        this.methodName = methodName;
    }


    /**
     * Return the name of the method to be overridden.
     */
    public String getMethodName() {
        return this.methodName;
    }

    /**
     * Return whether the overridden method is <em>overloaded</em> (i.e., whether argument
     * type matching needs to occur to disambiguate methods of the same name).
     */
    protected boolean isOverloaded() {
        return this.overloaded;
    }

    /**
     * Set whether the overridden method is <em>overloaded</em> (i.e., whether argument
     * type matching needs to occur to disambiguate methods of the same name).
     * <p>Default is {@code true}; can be switched to {@code false} to optimize
     * runtime performance.
     */
    protected void setOverloaded(boolean overloaded) {
        this.overloaded = overloaded;
    }

    @Override
    @Nullable
    public Object getSource() {
        return this.source;
    }

    /**
     * Set the configuration source {@code Object} for this metadata element.
     * <p>The exact type of the object will depend on the configuration mechanism used.
     */
    public void setSource(@Nullable Object source) {
        this.source = source;
    }

    /**
     * Subclasses must override this to indicate whether they <em>match</em> the
     * given method. This allows for argument list checking as well as method
     * name checking.
     *
     * @param method the method to check
     * @return whether this override matches the given method
     */
    public abstract boolean matches(Method method);


    @Override
    public boolean equals(Object other) {
        if (this == other) {
            return true;
        }
        if (!(other instanceof MethodOverride)) {
            return false;
        }
        MethodOverride that = (MethodOverride) other;
        return (ObjectUtils.nullSafeEquals(this.methodName, that.methodName) &&
                ObjectUtils.nullSafeEquals(this.source, that.source));
    }

    @Override
    public int hashCode() {
        int hashCode = ObjectUtils.nullSafeHashCode(this.methodName);
        hashCode = 29 * hashCode + ObjectUtils.nullSafeHashCode(this.source);
        return hashCode;
    }

}
